Turbomachinery, such as gas turbine engines, typically includes one or more rotor assemblies with circumferentially spaced blades mounted on an annular structure or disk. For example, axial flow gas turbine engines include a compressor section with one or more rotor assemblies for compressing air moving through the engine. Each compressor blade may include an airfoil and root separated by a platform. Various configurations for the root are known, with a dovetail shape being a paradigm. Each such dovetail root is mounted in the disk by means of either an axial slot or circumferential slot in the disk.
The present invention relates to dovetail roots mounted in a circumferentially extending slot. In order to reduce weight and ease mounting problems, such dovetails do not extend circumferentially as far as the overlying platform. This provides a gap between adjacent blade dovetails.
In axial flow compressors, air passing through a blade row increases in pressure. Gaps, such as described above, under blade platforms and between adjacent dovetails provide a leakage path through which the higher pressure air may backflow to the region of lower pressure. Such recirculation reduces compressor and overall engine efficiency.